Method for fabricating silicon targets

ABSTRACT

A method for fabricating silicon tiles and silicon tile targets has been provided, such as may be used in the sputter deposition of thin film transistor (TFT) silicon films. The method describes processes of cutting the tiles, beveling the tiles edges, etching the tiles to minimize residual damage caused by cutting the tiles, polishing the tiles to a specified flatness, and attaching the tiles to a backing plate. All these processes are performed with the aim of minimizing contamination and particle formations when the target is used for sputter deposition.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional of application Ser. No.09/862,107, filed May 21, 2001, entitled “System and Method forFabricating Silicon Targets,” invented by Voutsas et al., now U.S. Pat.No. 6,673,220.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention generally relates to integrated circuit (IC)fabrication and, more particularly, to a system and method for formingsilicon targets for use in sputter deposition processes.

[0004] 2. Description of the Related Art

[0005] Research continues into methods of producing polycrystalline(p-Si) film by annealing amorphous silicon (a-Si) films. Polycrystallinefilms are used in the formation of IC active areas, such as the source,drain, and gate regions of a transistor. One specific application is theformation of thin film transistors (TFTs) that are used in thefabrication of active matrix (AM) liquid crystal displays (LCDs).

[0006] One relatively recent approach to forming an amorphous siliconfilm is through silicon (Si) sputter deposition. Little prior art existsin this field, as the application of sputtering method for silicondeposition in microelectronics (i.e. TFTs) is quite new. There is a bodyof work in the use of silicon targets for sputtering of optical coatings(SiO2, SiNx), but this application differs. The optical coatings areparticularly valued for their optical characteristics, not theirelectrical characteristics. In some circumstances these optical coatingtargets are heavily doped to improve conductivity of the resulting film.However, a highly doped silicon film cannot be formed into a transistoractive area. Furthermore, these optical coatings are a continuousblanket films and, therefore, little regard is paid to particle size anduniformity. Transistor active area silicon films are patterned, however,often to small geometries. Therefore, the particle composition, oflittle regard in a blanket optical coating film, is critical in theformation of transistor silicon film.

[0007]FIGS. 1a through 1 e are partial cross-sectional diagramsillustrating the fabrication of a conventional top-gate TFT structure(prior art). Poly-Si (polycrystalline-Si) TFTs are made by a pluralityof processes. In the majority of polycrystalline silicon TFT LCDapplications, the so-called top-gate, polycrystalline silicon TFTstructure is used. Typically, Plasma-Enhanced Chemical Vapor Deposition(PE-CVD) or Low-Pressure CVD (LPCVD) is used to deposit the amorphoussilicon precursor. There are several advantages in using physical vapordeposition (PEV) or sputtering to form the silicon film. Such advantagesare a reduction in process steps, as there is no need fordehydrogenation, equipment cost reduction, and improved process safety,since no toxic/pyrophoric gases are necessary.

[0008] In FIG. 1a a barrier layer 10 is deposited over a substrate 12.Amorphous silicon is deposited over barrier layer 10 and annealed, usingan Excimer Laser for example, to form polycrystalline silicon layer 14.

[0009] In FIG. 1b the polycrystalline silicon layer 14 is patterned anddry etched.

[0010] In FIG. 1c a gate isolation layer 16 is formed over thepolycrystalline silicon layer 14. A gate 18 is formed over gateisolation layer 16, and the source region 20 and drain region 22 areimplanted with P material.

[0011] In FIG. 1d an interlayer dielectric 24 is isotropicallydeposited.

[0012] In FIG. 1e the interlayer dielectric 24 is selectively etched toform vias to the source/drain regions 20/22. A source contact 26 and adrain contact 28 are deposited and patterned. The present invention isconcerned with the sputter deposition of the amorphous silicon used tofrom polycrystalline silicon layer 14 (FIG. 1a).

[0013]FIG. 2 is a partial cross-sectional diagram of a typical DCmagnetron sputtering chamber (prior art). One of the key aspects of thesilicon-sputtering process is the ‘target’ component. The target is ablock of the material to be deposited, mounted on an appropriate metalbacking plate, and placed opposite to the substrate where the film is tobe deposited. Plasma strikes in the gap between the target and thesubstrate. The magnet that is scanning above the target backing plate isused to intensify the plasma and confine it in the region defined by themagnetic field. By scanning the magnet, the plasma is swept across thesurface of the target, resulting in deposition of the film on thesubstrate opposite to the target. The plasma is generated by applyinghigh voltage to an inert gas (typically Ar, but alternately He, Ne, Kror mixtures) that flows in the region between the target and thesubstrate. For certain applications, other gases may be mixed to thesputtering gas, such as H2, O2, N2, etc., to alter the compositionand/or the properties of the sputtered film.

[0014] The target is an important component of the sputtering processbecause it affects the level of contamination in the film, as well asthe level of particles, which are generated during the depositionprocess. Particles are fragments of silicon material that are detachedfrom the target material during processing. Particles larger thanapproximately 5 microns are not desirable in TFT process films. Hence,the target manufacturing must proceed in a way that the produced targetcan yield low levels of contamination in the deposited film as well as alow level of particles. High particle levels result in low yields, aswell as reduced equipment up-time, since frequent cleaning of thechamber is required. Film contamination needs to be reduced belowacceptable levels, for the films to be suitable for the fabrication ofelectronic devices.

[0015] The issue of particles is particularly severe for silicon targetsfor two reasons: (1) the target is a tiled assembly (not a singlepiece), which means that the edges of the tiles can generate particles,unless they are properly prepared; and, (2) the target material isgenerally of low resistivity (does not conduct thoroughly) as a resultof the purity requirements of the deposited film. Hence, the material issusceptible to charge buildup and, consequently, arcing, especially ifthe surface of the target is not properly conditioned. Arcing may resultin increased contamination in the film, especially with the materialthat the chamber and internal components being made of Al, Ni, orequivalent metals.

[0016] It would be advantageous if a process existed for efficientlysputtering silicon to form an amorphous silicon film.

[0017] It would be advantageous if the amorphous silicon film could besputter deposited without particle contaminants.

[0018] It would be advantageous if silicon targets existed thatminimized contamination in the sputter deposition of amorphous siliconfilm.

SUMMARY OF THE INVENTION

[0019] The present invention involves a procedure to produce silicontargets for use in microelectronics, particularly in the fabrication ofpolycrystalline silicon TFTs. The silicon tiles and resultant targetsdemonstrate excellent particle performance and reduced contaminationlevels in the deposited silicon-films.

[0020] Accordingly, a method is provided for forming silicon targettiles in the fabrication of integrated circuit (IC) sputter depositedsilicon films. The method comprises: cutting either single-crystal orpolycrystalline silicon tiles to a thickness in the range of 7millimeters (mm) to 10 mm; and, treating the silicon tile edges tominimize the generation of contaminating particles. The silicon tiletreatment includes subjecting the silicon tile top and bottom surfaceedges to a beveling or radiusing operation. The silicon tile top surfaceedges are beveled within the range of 1 mm to 5 mm, or radiused withinthe range of 3 mm to 10 mm. The silicon tile bottom surface edges arebeveled approximately 1.5 mm. Further, the silicon tile treatmentincludes beveling the silicon tile corners approximately 1.5 mm.

[0021] The method further comprises: chemically etching the silicon tilesurfaces to remove silicon material within the range of 50 microns (um)to 500 um; polishing the silicon tile top and bottom surfaces to apredetermined flatness in the range of 0.1 um to 10 um; and, attaching aplurality of the polished silicon tiles to a backing plate to form acompleted silicon target.

[0022] Additional details of the above-described silicon tile targetfabrication method and a silicon target device are described below.

BRIEF DESCRIPTION OF THE DRAWING

[0023]FIGS. 1a through 1 e are partial cross-sectional diagramsillustrating the fabrication of a conventional top-gate TFT structure(prior art).

[0024]FIG. 2 is a partial cross-sectional diagram of a typical DCmagnetron sputtering chamber (prior art).

[0025]FIG. 3 is a perspective view of the silicon target of the presentinvention that is used in the fabrication of IC sputter depositedsilicon films.

[0026]FIGS. 4a through 4 g feature detailed aspects of the silicon tileof FIG. 3.

[0027]FIG. 5 is a detailed depiction of the silicon tile bottom of FIG.4a to feature the backing plate attachment.

[0028]FIG. 6 is a partial cross-sectional view of FIG. 3, featuring thetile gap between the silicon tiles.

[0029]FIG. 7 is a flowchart illustrating a method for forming silicontarget tiles in the fabrication of integrated circuit (IC) sputterdeposited silicon films.

[0030]FIG. 8 is a flowchart illustrating an alternate method for aforming a silicon target in the fabrication of IC sputter depositedsilicon films.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present invention describes the fabrication of silicontargets using either single-crystal silicon material or usingpolysilicon material. The material of the target is important indetermining the number of tiles in the final target. A silicon targetwith a surface of 650 millimeters (mm) by 550 mm requires about 20single-crystal silicon (c-Si) tiles, but only 4 polysilicon (p-Si)tiles. The number of single-crystal tiles can be reduced by accepting anorientation of silicon material, other than the standard (100)crystallographic orientation. That is, the silicon tiles can be cutlengthwise from the silicon ingot. However, it is likely that a targetmade from single-crystal material will always include more tiles than asimilarly-sized target made from polycrystalline silicon material. Thenumber of tiles affects the overall area of tile edge as well as thenumber of tile gaps across the face of the target. For this reason, itis best to minimize the number of tile gaps in the target.

[0032]FIG. 3 is a perspective view of the silicon target of the presentinvention that is used in the fabrication of IC sputter depositedsilicon films. The target 300 includes a backing plate 302 and aplurality of silicon tiles 304 attached to the backing plate 302. Whensilicon tiles 304 are a polycrystalline silicon material, a plurality offour polycrystalline silicon tiles 304 are attached to the backing plate302, as shown. Alternately, but not shown, when silicon tiles 304 are asingle-crystal silicon material, a plurality of twenty single-crystalsilicon tiles 304 are attached to the backing plate 302. Preferably, thenumber of tiles needed to form a target is smaller than the above-statednumbers. The attached plurality of silicon tiles 304 forms a silicontarget 300 with the surface of approximately 650 mm by 550 mm. That is,a is 650 mm and b is 550 mm. However, other target dimensions arepossible.

[0033] The tiles are cut and shaped to size, from a block of theappropriate material. This should be accomplished by a process thatresults in the least mechanical damage. Residual cutting damage leavesresidual stresses, that may cause particle formation and generate arcingspots when the material is used in the sputtering chamber. Differentmethods are used to cut the tiles, such as: saw cutting, laser cutting,high pressure water, router, etc. Ion milling can be used after therough cut to precisely cut the tile to specifications. One method thatappears to minimize residual damage is saw-cutting followed by ionmilling. Regardless of the efforts taken and the cutting procedure used,any residual damage remaining after the cutting must be removed. If itis not, particles are generated from the surface of the tiles.

[0034] The preparation and treatment of the tile edges is described inthe following drawing explanations. The tile edge is initially beveledin the. 1-5 millimeter (mm) range. Beveling less than 1 mm appears to beineffective, while a beveling of 5 mm provides satisfactory results.Alternatively, the edge can be radiused. Radiusing requires a radius ofmore than 1 mm in order to be effective. A small bevel of approximately1.5 mm is introduced at the bottom of the tile to seal out contaminationthat may enter the gap between tiles. This feature becomes moreimportant as the target is eroded during sputter deposition, and thedistance between the top surface and the bottom surface of the tilebecomes smaller. If the bottom edge of the tile is not beveled,depending upon the original beveling size and the thickness of the tile,the plasma may actually reach the bottom of the tile gap and releaseimpurities.

[0035] Before the chemically etching of the tiles, the corners of thetiles are also beveled. The corner beveling is desirable from the pointof view of stress release, as sharp edges have higher stored stress thansmooth edges. To avoid chipping of the tile corners, small corner cutsare made in the four corners of each tile. These are beveled cuts ofabout 1.5 mm. This feature allows easier handling of the target tiles asthey are bonded on the backing plate. The corner cuts also protect thecorners from chipping during handling. Chipped corners create sites forparticle generation during sputter deposition.

[0036] Any damage caused as a result of the shaping (cutting) ortreating (beveling) processes is addressed by chemically etching-off thetiles to remove the damaged surface layers. The removal of at least 50microns (um) of silicon material is necessary, with 100-200 um beingmore typical, to effectively remove the damaged layers after milling.This etching process takes place by immersion in a HNO3/HF/CH3COOH(4:1:3) solution. Alternative chemistries include HF/HNO3 solutions(1:6-1:8). It is important to stir during etching to improve uniformity.A dump rinse is used to quickly remove the etchant from the surface ofthe silicon material, and to stop the etching process.

[0037] The tiles are polished to improve the surface flatness. Polishingis accomplished by lapping the surface using a small grit paper.Alternatively, polishing can be accomplished by a chemical mechanicalpolishing (CMP) method, with a SiO2 slurry for example. Equivalentslurries can also be used.

[0038]FIGS. 4a through 4 g feature detailed aspects of the silicon tile304 of FIG. 3. FIG. 4a is a partial cross-sectional view of the silicontile 304. Each silicon tile 304 has a predetermined thickness 400 in therange of 7 mm to 10 mm. Tile 304 also has treated top surface edges 402and treated bottom surface edges 404. The tile 304 has a top surface 406and a bottom surface 408 that is attached to the backing plate (see FIG.3).

[0039]FIG. 4b is a plan view of the top 406 of the silicon tile 304. Thefour top surface edges 404 can be seen. Although not shown here (seeFIG. 5), a plan view of the tile bottom surface would also show fourbottom surface edges in the same arrangement as the top surface edges402. The tile 304 also has treated corners 410.

[0040]FIG. 4c is a detailed partial cross-sectional view of the silicontile top surface 406. The top surface has a predetermined flatness 412.Although not shown, the tile bottom surface likewise has a predeterminedflatness. In some aspects of the invention, the flatness 412 is in therange of 5 microns (um) to 10 um. In other aspects the flatness 412 isin the range of 1 mm to 6 mm. In yet other aspects, the flatness 412 isin the range of 0.1 mm to 1 mm. These different flatness specificationsinvolve a trade off between process costs and the quality of thedeposited silicon film.

[0041]FIG. 4d is a detailed view of a top surface edge 402 of FIG. 4a,featuring the beveled edges. The silicon tile treated top surface edges402 are beveled within the range of 1 mm to 5 mm. That is, b is in therange of 1 to 5 mm.

[0042]FIG. 4e is a detailed view of the top surface edge 402 of FIG. 4a,featuring the radiused edges. The silicon tile treated top surface edges402 are radiused within the range of 3 mm to 10 mm. That is, r is in therange of 3 to 10 mm.

[0043]FIG. 4f is a detailed view of a bottom surface edge 404 of FIG.4a, featuring the beveled edges. The silicon tile treated bottom surfaceedges 404 are beveled are beveled approximately 1.5 mm. That is, b isapproximately 1.5 mm.

[0044]FIG. 4g is a detailed view of the treated corners 410 of FIG. 4b.The silicon tile treated corners 410 are beveled approximately 1.5 mm.That is, b is approximately 1.5 mm.

[0045] As mentioned above, the silicon tiles 304 are a material selectedfrom the group including single-crystal silicon (c-Si) andpolycrystalline silicon (p-Si). In some aspects of the invention thesilicon tiles 304 are a silicon material doped with a p-type dopant witha resistivity in the range from 0.5 to 50 ohms per centimeter. Astypically cut, the silicon tiles 304 have a (100) crystallographicorientation.

[0046]FIG. 5 is a detailed depiction of the silicon tile bottom 408 ofFIG. 4a to feature the backing plate attachment. An adhesive is formedon each silicon tile bottom surface 408, along the bottom surface edges404 to form an adhesive boundary 500. Indium 502, represented by thecross-hatched area, is placed on each silicon tile bottom surface 408,interior to the adhesive boundary 500. Indium may be evenly applied inthe interior area, as shown, or applied in a pattern. The adhesiveboundary 500 keeps the indium 502 under the tile 304, to prevent indiumcontamination in the deposition process.

[0047]FIG. 6 is a partial cross-sectional view of FIG. 3, featuring thetile gap between the silicon tiles 304. The silicon tiles 304 areseparated by a tile gap 600 in the range of 0.5 mm to 1 mm.

[0048]FIG. 7 is a flowchart illustrating a method for forming silicontarget tiles in the fabrication of integrated circuit (IC) sputterdeposited silicon films. Although the method has been depicted as asequence of numbered steps for clarity, no ordering should be inferredfrom this numbering unless explicitly stated. The method begins at Step700. Step 702 shapes silicon tiles. Shaping silicon tiles includescutting tiles from a silicon ingot or block using a method selected fromthe group including saw cutting, laser cutting, high pressure watercutting, and router cutting. The silicon tiles are usually shaped tohave a conventional (100) orientation, but other crystallographicorientations are possible. The shaping the silicon tiles includescutting the silicon tiles to a thickness in the range of 7 millimeters(mm) to 10 mm.

[0049] Shaping silicon tiles in Step 702 includes shaping silicon tilesfrom a material selected from the group including single-crystal silicon(c-Si) and polycrystalline silicon (p-Si). In some aspects the silicontiles are shaped from a silicon material doped with a p-type dopant witha resistivity in the range from 0.5 to 50 ohms per centimeter.

[0050] Step 704 treats the silicon tile edges to minimize the generationof contaminating particles. Step 704 treats the silicon tiles bysubjecting the silicon tile top and bottom surface edges to a treatmentselected from the group including beveling and radiusing. In Step 704 athe silicon tile top surface edges are beveled within the range of 1 mmto 5 mm. Alternately, the silicon tile top surface edges are radiusedwithin the range of 3 mm to 10 mm. In Step 704 b the silicon tile bottomedges are beveled approximately 1.5 mm.

[0051] Step 704 c includes subjecting the silicon tile corners to atreatment selected from the group including beveling and radiusing. Inone aspect the silicon tile corners are beveled approximately 1.5 mm.

[0052] Step 706, following the treating of the silicon tile edges inStep 704, chemically etches the silicon tile surfaces. Chemicallyetching the silicon tile surfaces includes removing silicon materialwithin the range of 50 microns (um) to 500 um. In some aspectschemically etching the silicon tile surfaces includes immersing thesilicon tiles in a solution selected from the group includingHMO3/HF/CH3COOH (4:1:3) and HF/HNO3 (1.6:1.8). Alternately, thechemically etching of the silicon tile surfaces in Step 706 includesimmersing the silicon tiles in a solution that is a mixture of HNO3 andHF, with traces of CH3COOH.

[0053] Step 708, following the chemically etching of the silicon tilesin Step 706, polishes the silicon tile top and bottom surfaces to apredetermined flatness. Polishing the silicon tile top and bottomsurfaces includes polishing the surfaces with a process selected fromthe group including sanding with small grit paper andchemical-mechanical polishing (CMP) with a SiO2 slurry. In some aspectspolishing the silicon tile top and bottom surfaces in Step 708 includespolishing the surfaces to a flatness in the range of 5 um to 10 um.Alternately, the flatness is in the range of 1 um to 6 um, or 0.1 mm to1 mm.

[0054] Step 710, following the polishing of the silicon tiles in Step708, attaches a plurality of the silicon tiles to a backing plate toform a completed silicon target. Attaching a plurality of the silicontiles to a backing plate to form a completed silicon target includesforming a silicon target with a surface of approximately 650 mm by 550mm. When the silicon tiles are shaped from a polycrystalline siliconmaterial in Step 702, four polycrystalline silicon tiles are typicallyattached to the backing plate. When the silicon tiles are shaped from asingle-crystal silicon material, twenty single-crystal silicon tiles areattached to the backing plate.

[0055] In some aspects attaching a plurality of silicon tiles to abacking plate in Step 710 includes attaching each tile with adhesiveplaced on the silicon tile bottom surface, along the bottom surfaceedges to form an adhesive boundary, with indium placed inside theadhesive boundary.

[0056]FIG. 8 is a flowchart illustrating an alternate method for aforming a silicon target in the fabrication of IC sputter depositedsilicon films. The method starts at Step 800. Step 802 cuts silicontiles to a thickness in the range from 7 mm to 10 mm. Step 804 subjectsthe silicon tile top and bottom surface edges to a treatment selectedfrom the group including beveling and radiusing. Step 806 bevels thesilicon tile corners approximately 1.5 mm. Step 808 chemically etchesthe silicon tile surfaces to remove silicon material within the range of50 microns (um) to 500 um. Step 810 polishes the silicon tile top andbottom surfaces to a predetermined flatness within the range of 0.1 umto 10 um. Step 812 attaches a plurality of the silicon tiles to abacking plate to form a completed silicon target. Attaching a pluralityof the silicon tiles to a backing plate to form a completed silicontarget in Step 812 includes forming a silicon target with a surface ofapproximately 650 mm by 550 mm.

[0057] In some aspects Step 804 includes the silicon tile top surfaceedges being beveled within the range of 1 mm to 5 mm. Alternately, thesilicon tile top surface edges are radiused within the range of 3 mm to10 mm. Step 804 also includes the silicon tile bottom surface edgesbeing beveled approximately 1.5 mm.

[0058] In some aspects of the invention Step 808 chemically etches thesilicon tile surfaces by immersing the silicon tiles in a solution thatis a mixture of HNO3 and HF, with traces of CH3COOH.

[0059] The invention is applicable to the fabrication of polysiliconthin film transistors (TFTs), such as might be used in liquid crystaldisplays (LCDs). However, improvements in the fabrication of TFTs wouldalso be applicable to other areas of IC technology such as X-ray imagingtechnology and sensor arrays, as well as specific products or productconcepts, such as sheet computer, sheet phone, sheet recorder, etc.Other variations and embodiments of the above-described invention willoccur to those skilled in the art.

We claim:
 1. In the fabrication of integrated circuit (IC) sputterdeposited silicon films, a method for forming silicon (Si) target tiles,the method comprising: shaping silicon tiles; and treating the silicontile edges to minimize the generation of contaminating particles.
 2. Themethod of claim 1 wherein shaping silicon tiles includes cutting tilesfrom a silicon ingot using a method selected from the group includingsaw cutting, laser cutting, high pressure water cutting, and routercutting.
 3. The method of claim 1 wherein shaping the silicon tilesincludes cutting the silicon tiles to a thickness in the range of 7millimeters (mm) to 10 mm.
 4. The method of claim 1 wherein treating thesilicon tiles includes subjecting the silicon tile top and bottomsurface edges to a treatment selected from the group including bevelingand radiusing.
 5. The method of claim 4 wherein the silicon tile topsurface edges are beveled within the range of 1 mm to 5 mm.
 6. Themethod of claim 4 wherein the silicon tile top surface edges areradiused within the range of 3 mm to 10 mm.
 7. The method of claim 4wherein the silicon tile bottom surface edges are beveled approximately1.5 mm.
 8. The method of claim 1 wherein treating the silicon tilesincludes subjecting the silicon tile corners to a treatment selectedfrom the group including beveling and radiusing.
 9. The method of claim8 wherein the silicon tile corners are beveled approximately 1.5 mm. 10.The method of claim 1 wherein shaping silicon tiles includes shapingsilicon tiles from a material selected from the group includingsingle-crystal silicon (c-Si) and polycrystalline silicon (p-Si). 11.The method of claim 1 wherein shaping silicon tiles includes shapingsilicon tiles from a silicon material doped with a p-type dopant with aresistivity in the range from 0.5 to 50 ohms per centimeter.
 12. Themethod of claim 1 further comprising: following the treating of thesilicon tile edges, chemically etching the silicon tile surfaces. 13.The method of claim 12 wherein chemically etching the silicon tilesurfaces includes removing silicon material within the range of 50microns (um) to 500 um.
 14. The method of claim 12 wherein chemicallyetching the silicon tile surfaces includes immersing the silicon tilesin a solution selected from the group including HMO3/HF/CH3COOH (4:1:3)and HF/HNO3 (1.6:1.8).
 15. The method of claim 12 wherein chemicallyetching the silicon tile surfaces includes immersing the silicon tilesin a solution that is a mixture of HNO3 and HF, with traces of CH3COOH.16. The method of claim 12 further comprising: following the chemicallyetching of the silicon tiles, polishing the silicon tile top and bottomsurfaces to a predetermined flatness.
 17. The method of claim 16 whereinpolishing the silicon tile top and bottom surfaces includes polishingthe surfaces with a process selected from the group including sandingwith small grit paper and chemical-mechanical polishing (CMP) with aSiO2 slurry.
 18. The method of claim 16 wherein polishing the silicontile top and bottom surfaces includes polishing the surfaces to aflatness in the range of 5 um to 10 um.
 19. The method of claim 16wherein polishing the silicon tile top and bottom surfaces includespolishing the surfaces to a flatness in the range of 1 um to 6 um. 20.The method of claim 16 wherein polishing the silicon tile top and bottomsurfaces includes polishing the surfaces to a flatness in the range of0.1 um to 1 um.
 21. The method of claim 16 further comprising: followingthe polishing of the silicon tiles, attaching a plurality of the silicontiles to a backing plate to form a completed silicon target.
 22. Themethod of claim 21 wherein attaching a plurality of the silicon tiles toa backing plate to form a completed silicon target includes forming asilicon target with a surface of approximately 650 mm by 550 mm.
 23. Themethod of claim 22 wherein shaping silicon tiles includes shaping thetiles from a polycrystalline silicon material; and wherein attaching aplurality of silicon tiles to a backing plate includes attaching fourpolycrystalline silicon tiles.
 24. The method of claim 22 whereinshaping silicon tiles includes shaping the tiles from a single-crystalsilicon material; and wherein attaching a plurality of silicon tiles toa backing plate includes attaching twenty single-crystal silicon tiles.25. The method of claim 21 wherein attaching a plurality of silicontiles to a backing plate includes attaching each silicon tile withadhesive placed on the silicon tile bottom surface, along the bottomsurface edges to form an adhesive boundary, with indium placed insidethe adhesive boundary.
 26. The method of claim 1 wherein shaping silicontiles includes shaping the silicon tiles having a (100) orientation. 27.In the fabrication of integrated circuit (IC) sputter deposited siliconfilms, a method for a forming a silicon (Si) target, the methodcomprising: cutting silicon tiles to a thickness in the range from 7millimeters (mm) to 10 mm; subjecting the silicon tile top and bottomsurface edges to a treatment selected from the group including bevelingand radiusing; beveling the silicon tile corners approximately 1.5 mm;chemically etching the silicon tile surfaces to remove silicon materialwithin the range of 50 microns (um) to 500 um; polishing the silicontile top and bottom surfaces to a predetermined flatness within therange of 0.1 um to 10 um; and, attaching a plurality of the silicontiles to a backing plate to form a completed silicon target.
 28. Themethod of claim 27 wherein subjecting the silicon tile top surface edgesto a treatment includes beveling the top surfaces edges within the rangeof 1 mm to 5 mm.
 29. The method of claim 27 wherein subjecting thesilicon tile top surface edges to a treatment includes radiusing the topsurface edges within the range of 3 mm to 10 mm.
 30. The method of claim27 wherein subjecting the silicon tile bottom surface edges to atreatment includes beveling the bottom surface edges approximately 1.5mm.
 31. The method of claim 27 wherein chemically etching the silicontile surfaces includes immersing the silicon tiles in a solution that isa mixture of HNO3 and HF, with traces of CH3COOH.
 32. The method ofclaim 27 wherein attaching a plurality of the silicon tiles to a backingplate to form a completed silicon target includes forming a silicontarget with a surface of approximately 650 mm by 550 mm.